Tungstophosphoric acids (PW) supported on various metal oxides (SiO 2 , γ-Al 2 O 3 , TiO 2 , ZrO 2 and CeO 2 ) were synthesized and used as catalysts for sorbitol dehydration to isosorbide for the first time. 30% PW/SiO 2 exhibited the best catalytic performance for sorbitol dehydration, over which 56% isosorbide selectivity could be gained at a 95% sorbitol conversion at 250 o C. The catalytic performance of regenerated 30% PW/SiO 2 catalysts by dichloromethane elution showed no loss after recycling five runs. Characterizations with UV-Vis, XRD, NH 3 -TPD and thermal analysis techniques revealed that PW had a good dispersion, and the primary Keggin structure was preserved after supporting PW on different supports. The interaction between PW and oxides resulted in different acidity of catalysts, which affected conversion of sorbitol and selectivity for isosorbide. The final acidity order of supported PW catalysts was the following: SiO 2 >γ-Al 2 O 3 >TiO 2 ≈ZrO 2 >CeO 2 .

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An efficient synthesis of 6-arylindazolo[2,3-a]quinolines starting from 2-aryl-2H-indazoles with sulfoxonium ylides via rhodium(III)-catalyzed C-H activation and cyclization reaction has been described. This transformation features high efficiency, tolerates various functional groups, avoids external oxidant and produces dimethyl sulfoxide (DMSO) and H2O as the sole by-products. In addition, the scale-up reaction demonstrated the practicability of this protocol in industry.

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